Chemical analysis of silicon-carbide-containing raw materials and refractory products

Modern silicon production technology is associated with a risk of negative environmental impact due to the fact that in addition to the final product, other reaction products are formed, including dust, from the incomplete use of charge materials. Gases released during silicon smelting in ore-thermal furnaces are characterized by the content of a large amount of fine dust. Dust consists of 94–96% of silicon dioxide. As a result of the use of sulfur-containing raw materials in furnaces as sulfur reducing agents, sulfur compounds in the form of SO2 are present in the furnace gases entering for purification, and nitrogen oxides are also present. The developed silicon recovery smelting technology reduces the technological energy consumption and increases the furnace productivity in proportion to the amount of carbon replaced by silicon carbide. Replacing carbon with silicon carbide reduces the dust content and the amount of exhaust furnace gases, and changes their composition. Thus, reducing the amount of pollutants reduces their anthropogenic impact on the environment. Keywords: silicon, gas cleaning dust, gas capture system, microsilica

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The Preparation and Properties of Clay Bonded Silicon Carbide by Using Silicon Carbide Dusting Powder

Materials Science Forum ◽

10.4028/www.scientific.net/msf.922.143 ◽

2018 ◽

Vol 922 ◽

pp. 143-148 ◽

Cited By ~ 2

Author(s):

Shao Chun Xu ◽

Zi Jing Wang ◽

Ya Ming Zhang ◽

Qiang Zhi ◽

Xu Dong Wang ◽

...

Keyword(s):

Silicon Carbide ◽

Ball Milling ◽

Bending Strength ◽

Sintering Temperature ◽

Raw Materials ◽

Clay Content ◽

Good Method ◽

Sintering Additive ◽

Carbide Refractory ◽

Milling Method

In this paper, clay bonded silicon carbide was prepared through pressureless sintering process with silicon carbide dusting powder as raw materials and clay as sintering additive. The effects of the ball-milling method, sintering temperature and clay contents on the density, microstructure and mechanical properties of clay bonded silicon carbide refractory were studied. The planetary ball-milling was a good method to improve the density of the green body, and the density was increased simultaneously with an increase of the clay content. The liquid phase derived from low-melting eutectic mixtures of clay could prevent the superlative oxidation of silicon carbide. The mass increment of sintered samples decreased firstly and then increased at the sintering temperature range from 1250 to 1500 °C. The open porosity of samples decreased with the clay addition at a content range from 10 to 30 wt.%. The bending strength of the samples decreased firstly and then increased with the clay addition increasing. The optimum condition for preparing clay bonded silicon carbide with silicon carbide dusting powder was sintering at 1350 °C with 20 wt.% clay, and the obtained sample with a porosity of 24% achieved the bending strength of 78±7 MPa.

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